A. Check install.txt for generic install problems. Then check here for unattended specific stuff.
1. Check MS's article on how to amend the unattended install files at :-
2. If you get an error "Configure SQLServer Agent / The server service is not started" installing MSDE on NT with the standard unattend.iss response file. Change AutoStart from 61455 to 255 in the unattend.iss file.